Adjustable curve



July 9, 1957 COOPER 2,798,299

ADJUSTABLE CURVE Filed March 1, 1956 Fig. 4

Franklin D. Cooper F/g 2 1 INVENTOR.

United States Patent Ofifice ADJUSTABLE CURVE D. Cooper, Evansville, Ind.

Application March 1, 1956, Serial No. 568,765

' 3 Claims. 01. 33 -177 The present invention relates to certain new and useful improvements in a structurally and functionally novel adjustable curve, that is, a variable plotting and scribing curve for use by draftsmen to aptly and satisfactorily solve the problem of ruling a smooth curve through any given set of points.

Flexible curve rules, bendably resilient splines and manually adjustable curves, broadly speaking, are not, of course, new. In fact, the art to which the invention relates is reasonably well developed and prior art constructions have already been devised to conform to and fit any contour down to a reasonably small radius and maintainthe contour while, with a pencil or pen, marking or inking, or tracing a curvilineal line.

The obviousobjective of the instant invention is to structurally, functionally and otherwise improve upon similarly constructed andperforming prior art so-called adjustable curves and, in doing so, to provide a novel structural adaptation in which manufacturers will find their manufacturing requirements and economies taken into account and met, suppliers of drafting equipment and implements will find a construction which they can reliably endorse, and draftsmen and other users will find their needs effectually met.

Briefly, the preferred embodiment of the invention is characterized by a plurality of complemental suitably shaped and sized weights. These are preferably of lead and are set upon the drawing board or other support surface. Cooperating therewith is an elongate flat-faced metal strip member which is, in effect, the guide rule. This preferably is disposed perpendicularly to the surface. One side thereof is attached to predetermined surfaces of the weights, the weights having permanent magnets to cause the selected portions of the strip member to adhere to and thus be supported on the weights.

Novelty is also predicated on having end weights with hold-down thumb tacks which serve to satisfactorily anchor the end blocks or weights. Novelty is also predicated on having the weights linked together so that they may pivot and move through paths of rotation approximating 180.

Other objects, features and advantages will become more readily apparent from the following description and the accompanying sheet of illustrative drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the views:

Figure 1 is a plan view illustrating the improved adjustable draftsmens curve and showing one manner in which the same is used to delineate a substantially J-shaped contour or line;

Figure 2 is a view on an enlarged scale and of a fragmentary nature showing several of the weights, a portion of the band or strip and other cooperating details;

Figure 3 is a horizontal sectional and elevational view on the plane of the line 33 of Figure 2 looking in the direction of the arrows; and,

Figure 4 is an exploded as well as enlarged perspective view illustrating the details with greater particularity.

2,798,299 Patented July 9, 1957 Referring now to the drawing and first to the complete drafting curve or implement shown in Fig. 1, it will be noted that the strip member is of elongate, flat-faced form and is denoted by the numeral 6 and it is preferably a flexibly resilient metal band having elongated slots 8 therein adjacent its opposite ends. These slotted ends are fastened by pins 10 having assembling and retaining heads 12. The pins are forced into and anchored in sockets 14 provided therefor in the two endmost weights or blocks 16 and 18. The strip member is disposed in what may be called a vertical position or at right angles to the surface of the drawing board, table or other surface, for instance, the drawing sheet (not shown). Each end block or weight has a vertical bore or passage 20 -therethrough to accommodate an insertable and removable hold-down pin 22 having a knob or head 24. This is, in effect, a so-called thurnb'tack and the purpose is to thus handily anchor the end weights on the support surface (not detailed). The surface may be said to be denoted generally at 26 in Fig. 2 wherein it will be seen that the lower edge 28 of the strip or band is in close proximity to the surface and parallel thereto. The portion of the band or strip between the two end blocks or Weights is also supported on and held down by complemental or auxiliary weights and these are denoted by the numerals 30. All of the weights may be said to be cylindrical in cross-section and they are preferably constructed of lead or an equivalent weighty material. The end weights 16 and 18 have side slots 32 therein while the intermediate auxiliary weights have diametrically opposite clearance slots of sector-shaped form and these are denoted by the numerals 34. All of the weights or blocks are provided with vertical holes 36 to accommodate hinge pintles or pins 38 which when fitted in place pass down through the holes across the slots 32 and 34 and through holes provided therefor in the ends of the horizontal assembling rigid links 40. Thus, all of the weights or blocks are linked together into a sort of a chain. On the desired surfaces the auxiliary blocks or weights are provided with horsehoe-shaped permanent magnets 42 which are embedded in place as shown in Fig. 3 and have their terminal ends or poles 44 and 46 exposed and attracted to and connected with the coopcrating vertical surface of the metal strip or band 6. It will be evident, therefore, that the instrument is constructed of solid lead cylinders and that the cylinders are provided at the bottom with rubber anti-slipping base members or so-called soles 48. The permanent magnets are preferably Alnico steel magnets with an approximate pull of 1 /2 pounds each. The hinging links are preferably of hard brass or copper and the manner in which the weights are chained or linked together allows the weights to pivot A practical model has been made and consists of 12 lead or equivalent weights with the end ones anchored by thumb tacks.

From the foregoing, the construction and operation of the device will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and chances will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A manually variable plotting and scribing curve for use by draftsmen comprising a flexibly resilient elongate strip member susceptible of being bent, curved, and shaped to enable the user to guide a marking pencil or an inking pen in a manner to either draw or trace a smooth curve through any given set of points, weights adapted to temporarily remain in erect positions atop a fixed support surface in a curvilineal line corresponding to the curvature of said strip member, said strip member being constructed of magnetizable metal, and permanent magnets embedded in certain of said weights, projecting'beyond vertical surfaces thereof and adhering to said strip member at selected'places alongthe length of said strip member, there being two end weights and a plurality of intervening complemental weights, said end weights being provided with thumb tacks for anchoring purposes, and the end portions of the strip being slotted and adjustably pinned to said end weights.

2. A manually variable plotting and scribing curve for use by draftsmen comprising a flexibly resilient elongate strip member susceptible of being bent, curved, and shaped to enable the user to guide a marking pencil or an inking pen in a manner to either draw or trace a smooth curve through any given set of points, weights adapted to temporarily remain in erect positions atop a fixed support surface in a curvilineal line corresponding to the curvature of said strip member, said strip member being constructed of magnetizable metal, and permanent magnets embedded in certain of said weights, projecting beyond vertical surfaces thereof and adhering to said strip member at selected places along the length of said strip member, there being two end weights and a plurality of intervening complemental weights, said end weights being provided with vertical bores having thumb tacks therein for anchoring purposes, the end portions of said strip being slotted and adjustably and removably pinned to said end weights, all of said weights being provided with anti-slipping base members, and means hingedly linking said weights together in chain-like form.

3. A manually variable plotting and scribing curve for I i weights having vertical bores extending therethrough from top to bottom, said bores adapted to accommodatingly retain insertable and removable thumb tacks which is used to anchor said end weights on said support surface, the bottom sides of all of said weights being provided with anti-slipping base members, said weight being provided between their top and bottom surfaces and cooperating sides with slots, hinge pins mounted in the respective weights, and bridging the respective slots, rigid links interposed between adjacent weights and pivotally connected with cooperating hinge pins and hingedly connecting the weights together in chain-like form, permanent magnets embedded in the intervening complemental weights and situated in horizontal planes midway between the top and bottom surfaces of the weights and exposed through corresponding sides of the respective complemental weights, a flexibly resilient elongate strip member susceptible of being bent, curved and shaped to enable the user to utilize it as a guide for a marking pencil andto in such manner draw or trace a smooth curve through any given set of points, predetermined portions of said strip member being magnetically connected with the cooperating permanent magnets, the end portions of said strip member being slotted and adjustably and removably pinned and thus fastened to the respective end weights.

References Cited in the file of this patent UNITED STATES PATENTS 764,482 Lord July 5, 1904 950,285 Harper Feb. 22, 1910 989,547 Gran Apr. 11, 1911 1,136,295 Szilard Apr. 20, 1915 1,797,842 Schmieder Mar. 24, 1931 2,487,944 Pressman Feb. 12, 1945 FOREIGN PATENTS 867 Great Britain 1904 

